POS1438 FRYQ QUESTIONNAIRE DISTINGUISHES INFLAMMATORY FROM NON-INFLAMMATORY DISEASE IN NEWLY REFERRED PATIENTS
Authors: R. Bos, A. Al Hasan, F. Reimann, A. M. Schilder, D. Zhang, F. Wink, L. Hendriks, T. Maarseveen, R. Knevel
Journal: Annals of the Rheumatic Diseases (2022)

Background Inflammatory Rheumatic Diseases (IRDs) affect 5% of the general population, while 35% of the population experiences Musculoskeletal Complaints (MSCs) [1]. IRDs cause early disability, reduced life-expectancy and considerable health care costs. Early diagnosis is essential to prevent long-term damage, similarly important is the early identification of patients with MSCs without IRDs to prevent unnecessary health care expenses. Of the population referred to the rheumatologist, 60% have non-inflammatory MSCs while only 20% of patients with an IRD see a rheumatologist within three months of symptom onset [2]. The need for digital predictive (triage) tools for Rheumatic and Musculoskeletal Diseases led to the development of the Frysian Questionnaire for differentiation of MSK complaints (FRYQ). Objectives To assess if FRYQ questionnaire can distinguish inflammatory rheumatic disease from non-inflammatory MSCs in newly referred patients. Methods The Frysian Questionnaire for differentiation of MSK complaints (FRYQ) is an 87 item questionnaire (consisting of 20 open questions and 67 closed questions), which is used in regular care in the rheumatology outpatient clinic of the Medical Center Leeuwarden to triage newly referred patients. Results of FRYQ, referral work diagnosis, resulting diagnoses and demographic data of 854 patients were collected. Elastic Net regularization was used to extract the most informative questions. The data was split: 75% to construct the elastic net and 25% to perform an independent validation. The classification performance was evaluated according to the area under the ROC-curve. Results The group consisted of 287 males (33%) and 570 (66%) females. Table 1 shows the characteristics of the 854 studied referrals. Table 1. Table 1 Referral orwork diagnosisNumber (%) Diagnosis by rheumatologist Number (%) Correct work diagnosis GPNumber (%) Rheumatoid arthritis 146 (16.9) 87 (10.1) 53 (36.3) Psoriatic arthritis 41 (4.8) 29 (3.4) 17 (41.5) Spondylarthropathy 64 (7.4) 52 (6.0) 30 (46.9) Undifferentiated oligoarthritis 97 (11.2) 10 (1.2) 5 (5.2) Polymyalgia rheumatica 55 (6.4) 27 (3.1) 22 (40.0) Gout 55 (6.4) 49 (5.7) 40 (72.7) Calcium pyrophosphate deposition 4 (0.5) 13 (1.5) 2 (50.0) Sarcoidosis 10 (1.2) 10 (1.2) 5 (50.0) Arthralgia 124 (14.4) 0 (0) Varied: mostly non inflammatory NA Clinically suspect arthralgia 0 18 (2.1) NA Reactive arthritis 2 (0.2) 12 (1.4) 1 (50.0) Sjögrens’ syndrome 14 (1.6) 6 (0.7) 2 (14.3) Systemic sclerosis 3 (0.3) 5 (0.6) 2 (66.7) Systemic lupus erythematosus 8 (0.9) 5 (0.6) 3 (37.5) GPA vasculitis 0 1 (0.1) 0 (0) Suspicion systemic auto immune disease 57 (6.6) 0 (varied: mostly non inflammatory) 0 (0) Tendomyalgia 27 (3.1) 117 (13.6) 10 (37.0) Fibromyalgia 79 (9.2) 110 (12.7%) 57 (72.2) Osteoarthritis 29 (3.4) 153 (17.7%) 22 (75.9) Hypermobility syndrome 0 23 (2.7) 0 (0) Unknown 6 0 NA Other 33 (3.9) 127* (14.8) NA total 854 (100) 854 (100) NA Inflammatory 293 (34.3 %)* Non-inflammatory 560 (65.7 %)* *including missing data After elastic net regularization the 87 items could be reduced to 33 items that were able to differentiate inflammatory disease from non-inflammatory disease with an AUC of 0.70 in the ROC curve below (Figure 1). Figure 1. ROC-curve highlighting performance of FRYQ after regularization in the validation set Conclusion FRYQ questionnaire can differentiate inflammatory rheumatic disease from non-inflammatory musculoskeletal complaints. To officially validate FRYQ a prospective cohort study is needed. References [1]van der Linden, M.W, Westert G.P, de Bakker, D.H et al. Tweede Nationale Studie naar ziekten en verrichtingen in de huisartspraktijk. https://www.nivel.nl/sites/default/files/bestanden/ns2_rapport1.pdf . Utrecht/Bilthoven: NIVEL/RIVM, 2004. [2]Stack RJ, Nightingale P, Jinks C, et al. Delays between the onset of symptoms and first rheumatology consultation in patients with rheumatoid arthritis in the UK: an observational study. BMJ Open 2019;9:e024361,2018-024361. Acknowledgements We thank our data managers and outpatient clinic secretariat. Disclosure of Interests None declared